Method and apparatus for removing scale from metal sheets

ABSTRACT

A method and apparatus are provided for removing scale from hot rolled steel sheets or strips by abrasion. Specifically, a roll comprising a hub with a multiplicity of generally radially extending flexible sheets is rotated at high speed, with the outer edges of the sheets in contact with the steel sheet passing thereby. Back-up rolls are provided for the abrasive rolls with two being used for thicker steel sheets and a single roll used for thinner sheets. The abrasive rolls and/or the back-up rolls are designed to be immediately retracted when the steel sheet is stopped, with the extent of retraction of the rolls being adjustable. When the sheet is stopped and before it is started again, it is reversed in direction a short distance to provide a slight overlap of the contact of the abrasive rolls with the steel sheet. The abrasive rolls are also oscillated slowly back and forth during operation to provide more uniform wear.

United States Patent Cauffiel 1 June 10, 1975 METHOD AND APPARATUS FOR REMOVING SCALE FROM METAL SHEETS Primary Examiner-Al Lawrence Smith Assistant Examiner-K. J. Ramsey Attorney. Agent, or FirmAllen D. Gutchess, Jr.

[76] Inventor: Ford B. Caufl'iel, 4940 Homerdale Ave., Toledo, Ohio 43623 22 Filed: July 23, 1973 [571 ABSTRACT A method and apparatus are provided for removing [2 l Appl' 381879 scale from hot rolled steel sheets or strips by abrasion. Specifically, a roll comprising a hub with a multiplicity [52] US. Cl. 51/39; 5l/78; 51/328 of generally radially extending flexible sheets is ro- [51] Int. Cl. B24!) 7/12 tated at high speed, with the outer edges of the sheets [53] Field O S fi 9, 76 R, in contact with the steel sheet passing thereby. Back- 328 up rolls are provided for the abrasive rolls with two being used for thicker steel sheets and a single roll [56] References Cited used for thinner sheets. The abrasive rolls and/or the UNITED STATES PATENTS back-up rolls are designed to be immediately retracted hen the steel sheet is stopped with the extent of re- 1.978.68l 101934 M G 51 328 w 2 297976 :19 s xfgi 5H3/9 X traction of the rolls being ad ustable. When the sheet 21702969 55 m D y 4 y 51/22 is stopped and before it is started again, it is reversed 3,126,674 3/1964 Burt 51/39 in direction a short distance to provide a slight overlap 3,416.261 l2/l968 Sherman et al. 5 [/76 R of the contact of the abrasive rolls with the steel sheet. 5 L |l/l970 Schaller el i 51/39 X The abrasive rolls are also oscillated slowly back and 3550-320 12/1970 Kenyon a] SW78 X forth during operation to provide more uniform wear. 3.609.919 lO/197l VanDorst 5l/39 X 4 Claims, 12 Drawing Figures M \30 -\o4- ree mac, ma 128 B4- 5 F fi ua i.- 98 as -l0 2 94 as we no a 84 es @6 g 7a w I 82 if Q I 10 "l4 M4- \92. 1m m4- is \50 6 H 164- Uas a 5* 1e I52 lirmdrn" I 56 Z Lno teo n2 W W lB 14 we 53 PATEmEnJuumrevs ABSQOAB SHEET 5 METHOD AND APPARATUS FOR REMOVING SCALE FROM METAL SHEETS This invention relates to a method and apparatus for removing scale from metal and specifically from hot rolled steel sheets or strips.

Heretofore, scale has been removed from hot rolled sheets primarily by pickling. The pickling process has had a number of disadvantages and problems. A pickling line is expensive and consumes considerable space, and is also hazardous because of the acid involved. To some extent, shot blasting also has been employed to remove scale from hot rolled steel. This process has a main disadvantage in that some of the scale tends to be embedded into the surface of the sheet, rather than being knocked off the sheet.

The present invention provides a unique method and apparatus for removing scale from hot rolled sheets. Accordingly, an abrasive roll is provided, having a hub with a miltiplicity of generally radially extending flexible abrasive sheets, with the abrasive surfaces extending in a common direction. The roll is rotated at high speed and the hot rolled sheet is directed past the roll in contact with the outer edges of the flexible sheets which effectively remove the scale quickly, easily, and cleanly. The abrasive sheets are effective in attacking the scale without having a serious effect on the steel surface thereunder. A plurality of the abrasive rolls are provided, with alternate rolls being on opposite sides of the steel sheet, and two back-up rolls preferably are spaced on opposite sides of a vertical line through the center of each abrasive roll. This arrangement keeps the abrasive roll out of contact with the back-up rolls where there is no sheet. For thinner sheets, a back-up roll is placed directly opposite the abrasive roll. In that instance, a plurality of plastic spacers are employed on the back-up roll to protect the shaft thereof. Mounts are employed in a manner such that a conversion from the double to the single back-up roll can be made quickly and easily.

In the hot rolled sheet line, the sheet must be stopped from time to time for such operations as shearing and welding. During this time the abrasive rolls must be quickly moved out of contact with the sheet. To accomplish this, the abrasive rolls or back-up rolls, or both, are mounted on pneumatic cylinders so as to be quickly withdrawn from the sheet. The extent of withdrawal is determined by adjustable stops which enable the contact of the rolls with the sheet once again to be accurately controlled. Also, after the sheet is stopped. it is reversed slightly before proceeding forwardly again so that a slight overlap of the contact of the abrasive rolls with the sheet can be achieved.

In another feature of the invention, the abrasive rolls and back-up rolls are slowly oscillated transversely of the sheet during operation. This provides more uniform wear on the abrasive rolls. The oscillation is controlled by sensing means engaging the edges of the sheet so that the length of osciallation can be immediately adjusted according to the width of the sheet being processed.

It is, therefore, a principal object of the invention to provide an improved method and apparatus for removing scale from metal sheets having the advantages outlined above.

Other objects and advantages of the invention will be apparent from the following detailed description of a preferred embodiment thereof, reference being made to the accompanying drawings, in which:

FIGS. 1A and 1B are a schematic view in elevation of an overall steel processing line embodying the invention',

FIGS. 2A and 2B are a schematic plan view of the steel processing line;

FIG. 3 is a side view in elevation of an abrasive roll and related components employed in removing scale from a metal sheet carried along the processing line;

FIG. 4 is a left end view in elevation of the apparatus of FIG. 3;

FIG. 5 is a somewhat schematic view taken along the line 55 of FIG. 3;

FIG. 6 is a side view in elevation of another abrasive roll and related components, this abrasive roll being on the opposite side of the sheet from that shown in FIG.

FIG. 7 is a left end view of the apparatus of FIG. 6;

FIG. 8 is a detailed view of certain components of the apparatus of FIGS. 6 and 7;

FIG. 9 is an end view of a backup roll arrangement using a single roll; and

FIG. 10 is a fragmentary view in vertical cross section taken along the line l0l0 of FIG. 9.

Referring to FIGS. 1A, 1B, and 2A, 2B, the overall steel processing line begins with a loading station indicated at 20. A plurality of coils 22 of sheets or strips or hot-rolled steel are supported on rails 24 and moved forwardly by pivotable dogs 26 to a lifting position on a pair of rolls 28 which lift the coil 22 by means of a fluid-operated ram 30 to a position between expandable mandrels 32. A sheet is peeled from the coil 22 by a peeler 34 of a type known in the art. The sheet is directed by the peeler 34 through a flattener 36 which includes two pairs of pinch rolls 38 between which is a process roll 40 which bends the steel strip as it passes thereby and lossens or breaks the scale thereon. The flattener 36 also includes five straightener rolls 42 which straighten the steel sheet passing therethrough. Beyond the flattener 36, is a shear 44 which cuts off the squares the trailing and leading edges of each steel sheet or strip passing therethrough. A welder 46 is located downstream of the shear 44 and welds together the abutting ends of two coils of strip. The sheet then passes through a polishing or abrading station 48 which removes the scale from the stip as will be discussed subsequently. Beyond the abrading station is an optional dry lubricator station 50 and a pair of pinch rolls 52. A shear 54 then cuts out the weld between two coils by removing a 6 to 8 inch wide portion of the strip. A recoiler 56 then rewinds the processed steel strip into a coil with oil being applied thereto by an oiler 58.

The abrading station 48 actually contains four units 60 which remove scale from the upper surface of the steel strip or sheet and four units 62 which remove scale from the lower surface of the steel sheet, only two of each type being shown. All eight of the units 60 and 62 preferably are self-contained within a housing 64 to confine to scale particles to a given space.

Referring to FIGS. 3-5, one of the units 60 is shown in more detail, and embodies an abrasive roll 66 in accordance with the invention. The roll includes a hub from which a multiplicity of flexible abrasive sheets extend in a general radial pattern. Common sides of the sheets have abrasive particles thereon and the roll is positioned so that edge portions of the sheets contact a steel sheet 68 as it passes thereby. The abrasive particles of the flexible sheets of the rolls tend to be finer in the units toward the downstream end of the abrading station 48.

The abrasive roll 66 is mounted on a shaft 70 which is rotatably journaled in depending bearing blocks 72 and 74 and driven at high speed through a gear box 76 by a motor 78. Below the abrasive roll 66 are two backup rolls 80 and 82 spaced on each side of a vertical line or plane extending through the center of the roll 66. This spaced arrangement of the back-up rolls prevents the abrasive roll 66 from contacting the back-up rolls 80 and 82 even if the sheet 68 is not present therebetween.

The bearing blocks 72 and 74 have sleeve bearings 84 and 86 respectively which are mounted for vertical movement on vertical rods 88 and 90 depending from cross frame members 92 and 94. These frame members, in turn, are affixed to horizontal rods or ways 96 and 98. The ways 96 and 98, in turn, extend through sleeve bearing blocks 100 and 102 which are affixed to an overhead supporting beam 104 constituting part of the housing 64. The gear box 76 and the motor 78 depend from the plate 106 which is affixed to the bearing 86 and an additional bearing 108 which is mounted for vertical movement on a vertical rod 110. The rod 110 is affixed to a transverse frame member 112 which is also affixed to the horizontal ways 96 and 98, the ways being further supported by bearing blocks 114.

With this arrangement, the abrasive roll 66 and all of the related components can be moved back and forth on the ways 96 and 98 which are slidably carried by the bearing blocks 100, 102, and 114. To so move the abrasive roll and components, a fluid-operated ram 116 (FIG. 5) is provided. This ram is mounted on cross members 118 and 120 extending between the main beams 104 and has a piston rod 122 affixed to the end frame member 92. The abrasive roll 66 thereby is slowly oscillated during its rotation in contact with the steel sheet 68, the main purpose of the oscillation being to provide more uniform wear on the abrasive roll 66 which as a practical necessity must be longer than the width of the sheet 68. Oscillation of the eight abrasive rolls is accomplished in staggered relationship to maintain a balance of transverse forces on the sheet. Preferably, all upper abrasive rolls move transversely in one direction and all lower rolls in the opposite direction.

To adjust the roll 66 vertically, along with the related components, a plurality of jackscrews 124, 126, and 128 are affixed to the bearing blocks 72, 74, and a transverse member (not shown) between the vertical rods 1 10. The jackscrews extend upwardly through rotatable nuts 130, 132, and 134 rotatably mounted on top ofthe frame members 92, 94, and 112. The nuts are rotated through worm gears 136 (FIG. 4) which are connected by shafts or rods 138 and 140 (FIG. 3). The rods. in turn, are driven through suitable drive means 142 supported by the rear transverse frame member 112. Thus, the adjustment of the roll 66 relative to the sheet 68 can be easily accomplished by driving the motor in either direction a predetermined amount.

The back-up rolls 80 and 82 are mounted on bearing blocks 144 and 146 which are mounted for vertical movement by sleeve bearings 148 and 150 on vertical rods or guides 152 and 154. When the steel sheet 68 is stopped, the sheet must be qdickly separated from the abrasive roll 66. For this purpose, the blocks 144 and 146 are mounted on fluid-operated rams 156 and 158, the piston rods of which can be quickly drawn into the cylinders to drop the blocks 144 and 146 and the back up rolls 80 and 82. The extent to which the back-up rolls are dropped or retracted is determined by adjustable stops 160 and 162 which engage stop plates 164 and 166 located below longitudinally extending frame members 168. The stops 160 and 162 are mounted on jackscrews 170 and 172 and are raised and lowered through gear boxes 174 and 176 which are driven through a common rod or shaft 178 by a crank which can be connected to a stub shaft 180 and operated from outside the housing. The extent of the retraction is primarily important from the standpoint that it controls the line of engagement of the back-up rolls 80 and 82 and the abrasive roll 66 with the sheet once again after the sheet is stopped and the rolls are withdrawn. This timing is important to assure that no gap exists in the contact between the abrasive roll and the sheet and yet that any overlap is not sufficient to cause a visible difference in the surface of the sheet. The retracted positions of the back-up rolls determines the line of contact more accurately than by varying the extent of reversal of the sheet after being stopped and before commencing again or by other means.

Additional adjustable stops 182 and 184 are also lo cated on the jackscrews 170 and 172, above the plates 164 and 166. These adjustable stops, which can be adjusted independently of the stops 160 and 162 determine the operating position of the back-up rolls 80 and 82 relative to the sheet 68 and the abrasive roll 66.

Referring now to FIGS. 6 and 7. one of the units 62 is shown in more detail, this unit operating on the lower surface of the sheet 68. The unit includes one of the abrasive rolls 66 which is mounted on the shaft 70 and rotatably journaled in the bearing blocks 72 and 74. The roll 66 again is driven through the gear box 76 by the motor 78. Above the abrasive roll 66 are the two back-up rolls 80 and 82 spaced on each side ofa vertical line or plane extending through the center of the roll 66 so as to prevent the abrasive roll from coming in contact with the back-up rolls. The bearing blocks 72 and 74 have the sleeve bearings 84 and 86 mounted on the vertical rods 88 and 90 which extend from the cross frame members 92 and 94. The frame members are mounted on the horizontal rods or ways 96 and 98 extending through the bearing blocks 100 and 102 which are affixed to a lower supporting beam 186 in this instance.

The gear box 76 and the motor 78 are supported on the plate 106 which is affixed to the bearing 86 and the additional bearing 108, the latter being mounted for vertical movement on the vertical rod 110. The rod 1 10 is affixed to the transverse frame member 112 which is also affixed to the horizontal ways 96 and 98. these being supported in the bearing blocks 114 in addition to the blocks 100 and 102. The abrasive roll 66 and the related components can be moved transversely on the ways 96 and 98 in the same manner as the unit 60 of FIGS. 5-7, and for the same purpose.

The roll 66 of the unit 62 again can be adjusted vertically through the jackscrews 124, 126, and 128 connected to the bearing blocks 72 and 74 and the member (not shown) between the rods 110. The jackscrews extend downwardly through the rotatable nuts 130, 132, and 134 rotatably mounted under the frame members 92, 94, and 112. The nuts are rotated through the worm gears 136 connected by the shafts 138 and 140 and driven through the drive means 142 supported by the member 112. i

The back-up rolls 80 and 82 are mounted on the blocks 144 and 146. which can be vertically moved by the bearings 148 and 150 slidably mounted on the vertical rods 152 and 154. The blocks 144 and 146 can be quickly raised by the fluid-operated rams 156 and 158 when the sheet is stopped, with the extent of retraction determined by the adjustable stops 160 and 162 which engage the stop plates 164 and 166 above the frame member 168. The stops 160 and 162 are mounted on the jackscrews 170 and 172 and are raised and lowered through the gear boxes 174 and 176 which can be driven through the common shaft 178 by rotation of the stub shaft 180. Again, the extent of retraction controls the point of contact of the back-up rolls relative to the sheet when it has been stopped and is once again started. The additional adjustable stops 182 and 184 determine the position of the back-up rolls relative to the sheet and are independently adjusted relative to the stops 160 and 162.

With the unit 62, when the sheet is stopped, it is raised to space it from the abrasive roll 66. For this purpose, referring to FIG. 8, a supporting surface 188 adjacent the lower roll 66 is mounted on a fluid-operated ram 190 and is raised when the sheet is stopped to separate it from the roll 166. The extent to which the sheet is raised preferably is less than the distance the back-up rolls are raised and at least no greater than that distance. In this regard, the surface 188 can be linked to the blocks 144 and 146 to move therewith. The timing achieved in abrading the steel sheet once again after it is in motion is still controlled primarily by the extent of retraction of the back-up rolls 80 and 82.

With thinner steel sheets 68, e.g., gauge and less, the spaced back up rolls 80 and 82 do not provide sufficient support for the sheet in contact with the roll 66. Accordingly, a back-up roll directly opposite the roll 66 is required in those instances. To achieve this, referring to FIGS. 9 and 10, an additional back-up roll 192 is rotatably mounted by stub shafts 194 in supporting plates 196 located at each end of the roll. When needed, the supporting plates 196 and the roll 192 can be quickly mounted on the bearing blocks 152 below the rolls 80 and 82, the plates being connected to the block 152 by a central bolt 198 and locating pins 200. In this instance, since the back-up roll is subject to being contacted by the abrasive roll 66, it is protected by a plurality of plastic cylindrical segments 202 which can be mounted on the roll 192 particularly adjacent the edges of the steel sheet 68 to protect the roll,

To control the length of oscillation of the rolls 66, a pair of limit switches designated LS1 and LS2 (FIGS. 6 and 7) are employed with the last of the units 62. The limit switches are mounted relative to the frame work for the lower roll 66 by suitable brackets 204 and 206. The limit switches control four-way valves to reverse the operation of the oscillating rams 116 (FIG. 5) when the edges of the steel sheet 68 are reached. Thus, the oscillation can be automatically regulated for a variety of widths of sheets.

Various modifications of the above described embodiments of the invention will be apparent to those skilled in the art and it is to be understood that such modifications can be made without departing from the scope of the invention, if they are within the spirit and the tenor of the accompanying claims.

I claim: 1 i

1.The method of removing scale from a steel sheet comprising moving said sheet in a given direction into contact with outer edge portions of a multiplicity of flexible sheets having abrasive surfaces while rotating said flexible sheets with their outer edges in a substantially circular path at high speed, supporting said steel sheet in contact with said flexible sheets through rotatable supports positioned on the side of said steel sheet opposite said flexible sheets, repeating the process on the opposite side of said steel sheet, stopping movement of said steel sheet in the given direction, substantially simultaneously separating said steel sheet from said flexible sheets by moving at least one of said steel sheet and said flexible sheets in a direction transverse to the steel sheet, moving said steel sheet in a direction opposite to the given direction to position a portion of the steel sheet previously in contact with the abrasive sheets near said abrasive sheets, again moving said steel sheet in contact with said flexible sheets so that said flexible sheets contact a portion of said steel sheet previously contacted by said flexible sheets, and again moving the steel sheet in the given direction.

2. Apparatus for removing scale from a metal sheet, said apparatus comprising a hub, a multiplicity of flexible sheets extending generally radially from said hub, each of said flexible sheets having an abrasive surface facing in a common direction, means for rotating said hub at a high speed in the common direction, means for supporting the metal sheet in contact with outer edge portions of said flexible sheets, means for moving said metal sheet in a given direction between said flexible sheets and said supporting means, said supporting means comprising two back-up rolls having axes parallel to the axis of said hub and located symmetrically on opposite sides of a vertical plane extending through the axis of said hub, and positioned to engage the metal sheet at the same time and to support it in contact with the outer edge portions of said flexible sheets, an additional back-up roll, and means for mounting said additional back-up roll with its axis in the plane extending through the axis of said hub and spaced toward said hub from said two back-up rolls.

3. Apparatus for removing scale from a metal sheet, said apparatus comprising means for directing the metal sheet along a predetermined path, an upper abrasive roll located above said path and positioned to contact an upper surface of the metal sheet when moving along the path, at least one back-up roll positioned on the side of the path opposite said abrasive roll to support the sheet in contact with said upper abrasive roll, means for rotating said abrasive roll at high speed, a lower abrasive roll located below the path and positioned to contact a lower surface of the sheet when moving along the path, at least one additional back-up roll located on the side of the path opposite said lower abrasive roll to support the sheet in contact with the lower abrasive roll, means for rotating said lower abrasive roll at high speed, means for engaging said metal sheet on the same side thereof as said lower abrasive roll, and means for raising said engaging means when the metal sheet is stopped to separate the metal sheet from said lower abrasive roll.

4. Apparatus for removing scale from a metal sheet, said apparatus comprising means for directing the roll located on the side of the path opposite said lower abrasive roll to support the sheet in contact with the lower abrasive roll, means for rotating said lower abrasive roll at high speed, means for moving said upper and lower rolls back and forth substantially axially and in opposite directions, and means engageable with opposite edge portions of the metal sheet to control the length of axial movement of said upper and lower rolls. 

1. The method of removing scale from a steel sheet comprising moving said sheet in a given direction into contact with outer edge portions of a multiplicity of flexible sheets having abrasive surfaces while rotating said flexible sheets with their outer edges in a substantially circular path at high speed, supporting said steel sheet in contact with said flexible sheets through rotatable supports positioned on the side of said steel sheet opposite said flexible sheets, repeating the process on the opposite side of said steel sheet, stopping movement of said steel sheet in the given direction, substantially simultaneously separating said steel sheet from said flexible sheets by moving at least one of said steel sheet and said flexible sheets in a direction transverse to the steel sheet, moving said steel sheet in a direction opposite to the given direction to position a portion of the steel sheet previously in contact with the abrasive shEets near said abrasive sheets, again moving said steel sheet in contact with said flexible sheets so that said flexible sheets contact a portion of said steel sheet previously contacted by said flexible sheets, and again moving the steel sheet in the given direction.
 2. Apparatus for removing scale from a metal sheet, said apparatus comprising a hub, a multiplicity of flexible sheets extending generally radially from said hub, each of said flexible sheets having an abrasive surface facing in a common direction, means for rotating said hub at a high speed in the common direction, means for supporting the metal sheet in contact with outer edge portions of said flexible sheets, means for moving said metal sheet in a given direction between said flexible sheets and said supporting means, said supporting means comprising two back-up rolls having axes parallel to the axis of said hub and located symmetrically on opposite sides of a vertical plane extending through the axis of said hub, and positioned to engage the metal sheet at the same time and to support it in contact with the outer edge portions of said flexible sheets, an additional back-up roll, and means for mounting said additional back-up roll with its axis in the plane extending through the axis of said hub and spaced toward said hub from said two back-up rolls.
 3. Apparatus for removing scale from a metal sheet, said apparatus comprising means for directing the metal sheet along a predetermined path, an upper abrasive roll located above said path and positioned to contact an upper surface of the metal sheet when moving along the path, at least one back-up roll positioned on the side of the path opposite said abrasive roll to support the sheet in contact with said upper abrasive roll, means for rotating said abrasive roll at high speed, a lower abrasive roll located below the path and positioned to contact a lower surface of the sheet when moving along the path, at least one additional back-up roll located on the side of the path opposite said lower abrasive roll to support the sheet in contact with the lower abrasive roll, means for rotating said lower abrasive roll at high speed, means for engaging said metal sheet on the same side thereof as said lower abrasive roll, and means for raising said engaging means when the metal sheet is stopped to separate the metal sheet from said lower abrasive roll.
 4. Apparatus for removing scale from a metal sheet, said apparatus comprising means for directing the metal sheet along a predetermined path, an upper abrasive roll located above said path and positioned to contact an upper surface of the metal sheet when moving along the path, at least one back-up roll positioned on the side of the path opposite said abrasive roll to support the sheet in contact with said upper abrasive roll, means for rotating said abrasive roll at high speed, a lower abrasive roll located below the path and positioned to contact a lower surface of the sheet when moving along the path, at least one additional back-up roll located on the side of the path opposite said lower abrasive roll to support the sheet in contact with the lower abrasive roll, means for rotating said lower abrasive roll at high speed, means for moving said upper and lower rolls back and forth substantially axially and in opposite directions, and means engageable with opposite edge portions of the metal sheet to control the length of axial movement of said upper and lower rolls. 